Australian Prime Minister Tony Abbott today pledged to “get to the bottom of the mystery” behind the missing Malaysia Airlines jet, as about 1,100 people continued to comb the India Ocean for wreckage.

Abbott said “we owe it” to the families and governments of missing citizens and the plane to “get to the bottom of the mystery”.

In comments which will be welcomed by families of doomed flight MH370, Abbott said: “I’m certainly not putting a time limit on it. We can keep searching for quite some time to come. The intensity of our search, the magnitude of our operation, is increasing not decreasing.”

However, the Australian prime minister said all the evidence suggested the plane had come down south of the Indian Ocean.

Speaking after a visit to the Pearce Air Base, where multinational search aircraft take off everyday to comb through thesouthern Indian Ocean, Abbott said moral of the searchers remained "high".

"They are tired, sure. But this is what they are trained for," he said.

A total of 100 personnel are flying in the air and another 1,000 working on the sea to search for evidence on what happened tothe Boeing 777 jet, which went missing less than an hour after it took off on March 8 from Kuala Lumpur en route to Beijing. At least five other countries are involved in the hunt for wreckage of flight MH370.

"To see the cooperation with us from China, Japan and Korea is really heartening and demonstrates that in a humanitarian cause the nations of the region can come together...and try to bring peace and closure to the 239 passengers of the ill-fated aircraft," Abbott said.

“It’s only reasonable that we should bear this cost. It’s an act of international citizenship on Australia’s part.” But Abbott warned some kind of “reckoning” would need to be realising – that he would not authorise a blank cheque. Canberra will bear the running cost of the coordination centre.

Former Defence chief Angus Houston, who was appointed to coordinate the search and investigation of the incident, said some families of the 239 people on board of the missing plane had expressed interest to come to Perth. But it is not sure when they would arrive.

The Australian Maritime Safety Authority said 10 planes and 10 ships are set to continue to search today.

“This is an extraordinarily difficult exercise. We are searching a vast area of ocean and we are working on quite limited information,” the Australian prime minister said, defending the revised search area for the plane. “If this mystery is solvable, we will solve it.”

“We’re as good as anyone in the world at it, and if any organisation is capable of coming up with an answer, it’s the Australian Maritime Safety Authority,” Abbott insisted.